upstream of the gas supply connection to the furnace and down-
stream of the manual shut-off valve is not required. Place a ground
joint union between the gas control manifold and the manual
shut-off.
Install a sediment trap in the riser leading to the furnace. The trap
can be installed by connecting a tee to the riser leading from the
furnace. Connect a capped nipple into the lower end of the tee. The
capped nipple should extend below the level of the gas controls.
(See Fig. 10.)
Piping should be pressure tested in accordance with local and
national plumbing and gas codes before the furnace has been
attached. If the test pressure exceeds 0.5 psig (14-in. wc), the gas
supply pipe must be disconnected from the furnace and capped
before the pressure test. If the test pressure is equal to or less than
0.5 psig (14-in. wc), close the manual shut-off valve before the
test. (See Fig. 10.) It is recommended that the ground joint union
be loosened before pressure testing.
After all connections have been made, purge the lines and check
for gas leakage with regulated gas supply pressure.
Step 8—Electrical Connections
115-V WIRING
Refer to the unit rating plate or Table 5 for equipment electrical
requirements. The control system requires an earth ground for
proper operation.
Fig. 7—Typical Attic Installation
A82178
30-IN. MIN
WORK AREA
6
″
MIN
FLUE VENT
GAS
ENTRY
24
″
24
″
SHEET
METAL
SEDIMENT TRAP
LINE CONTACT ONLY PERMISSIBLE BETWEEN
LINES FORMED BY INTERSECTIONS OF
THE TOP AND TWO SIDES OF THE FURNACE
JACKET AND BUILDING JOISTS,
STUDS, OR FRAMING.
Table 3—Filter Retainer (In.)
FURNACE CASING WIDTH
FILTERS
D
14-3/16
(2) 14 X 20 X 1
14-3/8
17-1/2
(2) 14 X 20 X 1
13-3/8
21
(2) 16 X 20 X 1
11-5/8
24-1/2
(2) 16 X 20 X 1
10-1/4
Fig. 8—Horizontal Filter Arrangement
A82173
FIELD-SUPPLIED
FILTER RETAINERS
AIRFLOW
D
12
″
4
″
Fig. 9—Downflow Filter Arrangement
A88486
RETURN-AIR
PLENUM
AIRFLOW
ACCESS DOOR
INSTALLATION
POSITION
OF FILTERS
7